TGG (Terbium Gallium Garnet)

Thermal conductivity is an order of magnitude greater than typical glass.

Optical losses are lower for TGG than Tb-doped glasses.​

Material Properties​

​ Formula:

​Tb3Ga5O12

Crystal Structure:

[111]

​Extinction Ratio (over 2/3 clear aperture):

​30 dB

Verdet Constant (632 nm)​:

​-134 RadT-1m-1

Verdet Constant (1064 nm):​

-40 RadT-1m-1

Thermal Conductivity​:

7.4 W cm-1 K-1

​Refractive Index:

​1.95​

Nonlinear Index, n2:

8.0

​Figure of Merit, V/a:

27

Figure of Merit, V/n2:

​5

Applications

Faraday Rotators and Isolators

Advantages

TGG has twice the Verdet constant of a terbium-doped glass.

The thermal conductivity of crystalline TGG is an order of magnitude greater than a typical glass.

Optical losses are lower for TGG than Tb-doped glasses.

The combination of the above factors make TGG better suited to high average power applications. The principal limiting factor is thermally induced beam distortion. Beam distortion is less for TGG than Tb-doped glasses under the same power loading level.